Gas supply apparatus

ABSTRACT

A gas ejector of a gas supply apparatus includes a nozzle portion. The opening of a first-stage restricting cylinder constituting the nozzle portion has a circular cross-sectional shape with a diameter r1. A second-stage restricting cylinder is continuously formed with the first-stage restricting cylinder along a Z direction. The opening of the second-stage restricting cylinder has a circular cross-sectional shape with a diameter r2, and supplies a source gas supplied from the first-stage restricting cylinder to a low-vacuum processing chamber below. At this time, the diameter r2 is set to satisfy “r2&gt;r1”.

TECHNICAL FIELD

The present invention relates to a gas supply apparatus for a filmformation process.

BACKGROUND ART

In the field of semiconductor manufacturing, processes such as a filmformation process of forming an insulating film or the like on asubstrate of an object to be processed such as a wafer, and etching,cleaning, and the like of a film surface formed by film formation areperformed. These processes are required to be performed at high speedand with high-quality techniques. For example, together with varioushigh-performance and excellent film formation processes including filmformation of a highly insulating thin film, a semiconductor thin film, ahigh dielectric thin film, a light-emitting thin film, a highly magneticthin film, a super-hard thin film, and the like, an etching process,peeling, and a cleaning process with high quality have been pursued.Realization of high-quality and uniform film formation on a surface of awafer (surface of a substrate to be processed) having a large area andhigh processing speed are highly valued.

The various thin-film techniques, and etching, peeling and cleaningprocesses described above have been applied not only to semiconductorelements but also to various fields of application.

In particular, among them, in the thin-film formation technique, a basictechnique of promoting nitriding, oxidation and hydrogen bonding bychemical reaction on a surface of a substance such as a metal or aninsulator material is important in thin-film formation. Based on thisbasic technique, a thin film is subjected to various heat treatments andchemical-reaction processes, and thus high-quality thin-film formationis realized.

Specifically, in the manufacture of a semiconductor device, there arefilm formation methods of high-function films such as a low-impedancehighly conductive film functioning as circuit wiring in a semiconductorchip, a highly magnetic film having a wiring coil function or a magnetfunction of a circuit, a high dielectric film having a capacitorfunction of a circuit, and a highly insulating film having a highinsulating function with a little electrical leakage current, the highlyinsulating film formed by oxidation or nitriding. In order to realizethese film formation methods for high-function films, a thermal CVD(Chemical Vapor Deposition) apparatus, a photo-CVD apparatus, a plasmaCVD apparatus, a thermal ALD (Atomic Layer Deposition) apparatus, or aplasma ALD apparatus is used. In particular, plasma CVD/ALD apparatusesare often used. For example, the plasma CVD/ALD apparatus isadvantageous in that the plasma CVD/ALD apparatus has lowerfilm-formation temperature and can perform a film formation processfaster in a shorter time than a thermal/photo CVD/ALD apparatus.

For example, in a case where a gate insulating film such as a nitridefilm (SiON, HfSiON or the like) or an oxide film (SiO₂. HfO₂) is formedon a wafer which is a substrate to be processed, the following techniqueusing a plasma CVD/ALD apparatus is generally adopted.

The thermal CVD/ALD apparatus heats the wafer and the inside of acontainer to increase reactivity of a supply gas to form a film on thewafer however, if the wafer is exposed to a high temperature, thermaldamage or the like leads to a decrease in yield.

Therefore, nowadays, film formation with plasma CVD/ALD using plasma isoften used in lieu of thermal CVD/ALD. (Plasma) CVD/ALD techniques aredisclosed in, for example, Patent Documents 1 to 3.

In a conventional film formation processing apparatus using plasmaCVD/ALD, thermal CVD/ALD or the like as disclosed in Patent Document 1,a method is adopted in which the film formation apparatus is filled withgas and the filled gas is activated by plasma energy or thermal energy,and a thin film is deposited by a chemical reaction process with the gassupplied to a surface of a wafer. The activated gas filled in the filmformation processing apparatus only has a random gas flow velocity dueto Brownian motion, and a gas particle itself does not have high speed.Therefore, the method is effective for a deposition film formationreaction on a surface of a substrate, but is not suitable for uniformlyforming a film on an extremely uneven surface of a substrate and foruniformly forming a three-dimensional film surface. In addition, in thecase of a highly reactive gas, since chemical reaction time is short,the lifetime is very short. Therefore, there is a disadvantage thatreaction is promoted only on a surface of a substrate, a supply gas doesnot reach an extremely uneven surface with high aspect ratio, anduniform film formation cannot be performed. In this case, it isnecessary to lead a reactant gas to the inside of a wafer in a shorttime so that film formation is performed by uniformly carrying outreaction even inside the wafer, or to give energy to gas filled insidethe wafer to convert the gas into an activated gas.

In a CVD/ALD film formation processing apparatus disclosed in PatentDocument 2, gas is uniformly supplied into a container and deposited onentirety of a wafer. However, there is a problem that in a case wherereactivity of the gas is high, the gas loses the reactivity beforereaching the wafer. Therefore, there are known a method of generatingplasma in a container to generate a highly reactive gas and supplyingthe gas to a substrate, and a method of increasing the temperatureinside a container or a wafer to increase reactivity.

In a plasma CVD/ALD apparatus using plasma disclosed in Patent Document3, energy of plasma is given to gas being supplied, and the gas isconverted into a highly reactive gas and supplied. In that case, thereis an advantage that the temperature inside a wafer or a container canbe set lower than the temperature in the case of thermal film formation;however, since a plasma generation source and a surface to be processedare required to be located close to each other, there is a disadvantagethat the substrate itself, which is located close to the plasmageneration source, is damaged due to an influence of plasma. Inaddition, when the conventional CVD/ALD film formation processingapparatus and the currently operating plasma CVD/ALD apparatus arecompared with each other, the currently operating plasma CVD/ALDapparatus is suitable for a three-dimensional film formation process ona relatively less uneven surface of a wafer. However, it issubstantially impossible to realize a three-dimensional film formationprocess on a more uneven surface of a wafer having higher aspect ratioand to obtain a high-quality three-dimensional film formation structure.

In a manufacturing method for manufacturing athree-dimensional-structure semiconductor disclosed in Patent Document4, it is necessary to form a uniform barrier film located around a TSV(through-silicon via) structure. In this case, there is limitation inuniform film formation in the depth direction. Therefore, the barrierfilm to be formed is divided into a plurality of layers in the depthdirection, and several layers are formed each time.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese Patent Application Laid-Open No.    2004-111739-   Patent Document 2: Japanese Patent Application Laid-Open No.    2013-219380-   Patent Document 3: Japanese Patent Application Laid-Open No.    2001-135628-   Patent Document 4: Japanese Patent Application Laid-Open No.    20014-86498

SUMMARY Problem to be Solved by the Invention

As described above, in the conventional thin-film formation techniques,since the film formation process is performed by supplying a supply gasand setting the inside of the film formation processing apparatus at apredetermined pressure, it is not necessary to supply gas havingdirectivity at high speed. Therefore, the conventional thin-filmformation techniques are not suitable for a film formation process foran uneven surface, which has been recently demanded. The techniques areparticularly not suitable for a film formation process for a waferhaving high aspect ratio, a representative example of which is a waferhaving a deep hole.

In addition, a method is suitable for supplying a highly reactive gas toa surface of a wafer in a short time. In the method, a singlerestricting cylinder (orifice) is provided as means for quicklysupplying gas to a low-vacuum processing chamber to increase gas supplyspeed, the gas is ejected in a low-vacuum environment in the low-vacuumprocessing chamber, and thus, the gas is ejected at an ultra-high speedexceeding Mach. In that case, it is necessary to set the pressuredifference between the pressure in a gas supply apparatus and thepressure in the low-vacuum processing chamber in a low-vacuum state tobe greater than or equal to a predetermined pressure ratio. As thepressure difference is greater or the pressure inside the low-vacuumprocessing chamber is lower, the gas is supplied at higher speed and thegas can be supplied on the surface of the wafer in a shorter time. Ifthe diameter of the opening of a flow path in the restricting cylinderis reduced and the pressure difference is increased, flow velocitybecomes faster and thus gas supply time becomes shorter.

However, in a case of ejecting gas at an ultra-high speed exceedingMach, the gas speed affects a gas flow velocity frame (gas jet speed) atthe gas impact pressure and the temperature condition of Mach speed, andbrings about an effect of extremely lowering the gas flow velocity at acertain ejection position. As a result, a phenomenon called a Mach diskcondition (condition where the gas flow velocity is extremely lowered ata certain ejection position) occurs. It is preferable to minimize thephenomenon of this Mach disk condition; however, no specific solutionhas been found.

The present invention solves the above-described problems. An object ofthe present invention is to provide a gas supply apparatus capable ofeffectively suppressing a phenomenon in which extreme deceleration ofgas occurs in association with an impact pressure and a temperaturecondition generated by a gas supplied to a substrate at an ultra-highspeed exceeding Mach when the gas is supplied to the substrate at theultra-high speed.

Means to Solve the Problem

A gas supply apparatus according to the present invention includes: amounting portion for mounting a substrate to be processed; and a gasejector which is provided above the mounting portion and supplies gasfrom a processing chamber having an opening on a bottom surface to thesubstrate to be processed. The gas ejector includes: a primaryaccommodating chamber which temporarily accommodates gas supplied from agas supply port; the processing chamber; and a nozzle portion which isprovided between the primary accommodating chamber and the processingchamber. The nozzle portion has: a first restricting cylinder whoseopening has a circular cross-sectional shape with a first diameter inplan view, and which supplies the gas in the primary accommodatingchamber downward; and a second restricting cylinder whose opening has acircular cross-sectional shape with a second diameter in plan view, andwhich supplies the gas supplied from the first restricting cylinder tothe processing chamber. The first diameter is set such that pressuredifference between the primary accommodating chamber and the processingchamber is greater than or equal to a predetermined pressure ratio. Thesecond diameter is set to be longer than the first diameter.

Effects of the Invention

In the gas ejector of the gas supply apparatus of the present inventionaccording to claim 1, the first restricting cylinder having the firstdiameter in the nozzle portion can give directivity to gas to be ejectedto the processing chamber. Thus, gas can be supplied to the substrate tobe processed at an ultra-high speed exceeding Mach. In this case, due toexistence of the second restricting cylinder provided between the firstrestricting cylinder and the processing chamber, it is possible tosuppress a Mach disk phenomenon in which ejected gas is extremelydecelerated by the impact pressure and the temperature conditiongenerated by the gas ejecting at an ultra-high speed.

As a result, the gas supply apparatus of the present invention accordingto claim 1 has the effect of being able to supply gas suitable for filmformation on a surface of a wafer with high aspect ratio to a substrateto be processed.

The objects, features, aspects, and advantages of the present inventionwill become more apparent from the following detailed description andthe accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory view illustrating a configuration of a gassupply apparatus according to Embodiment 1 of the present invention.

FIG. 2 is an explanatory view illustrating a configuration of a gassupply apparatus according to Embodiment 2 of the present invention.

FIG. 3 is an explanatory view illustrating a configuration of a gassupply apparatus according to Embodiment 3 of the present invention.

FIG. 4 is an explanatory view (part 1) illustrating a configuration of agas supply apparatus according to Embodiment 4 of the present invention.

FIG. 5 is an explanatory view (part 2) illustrating the configuration ofthe gas supply apparatus according to Embodiment 4 of the presentinvention.

FIG. 6 is an explanatory view illustrating a configuration of a gassupply apparatus according to Embodiment 5 of the present invention.

FIG. 7 is an explanatory view schematically illustrating a speedcondition of a gas jet using the gas supply apparatus according toEmbodiment 1.

FIG. 8 is an explanatory view schematically illustrating a pressurecondition of a gas jet using the gas supply apparatus according toEmbodiment 1.

FIG. 9 is an explanatory view schematically illustrating a speedcondition of a gas jet using a conventional gas supply apparatus.

FIG. 10 is an explanatory view schematically illustrating a pressurecondition of the gas jet using the conventional gas supply apparatus.

FIG. 11 is an explanatory view schematically illustrating a speedcondition of a gas jet in a case where the pressure ratio of a primaryaccommodating chamber to a low-vacuum processing chamber is less than 30times.

FIG. 12 is an explanatory view schematically illustrating a pressurecondition of the gas jet in a case where the pressure ratio of theprimary accommodating chamber to the low-vacuum processing chamber isless than 30 times.

FIG. 13 is an explanatory view schematically illustrating a Mach diskgeneration structure in the case of using the conventional gas supplyapparatus.

FIG. 14 is an explanatory view schematically illustrating effects in thecase of using the gas supply apparatus according to the presentembodiment.

DESCRIPTION OF EMBODIMENTS Embodiment 1

FIG. 1 is an explanatory view illustrating a configuration of a gassupply apparatus according to Embodiment 1 of the present invention. InFIG. 1, an XYZ orthogonal coordinate system is illustrated.

As illustrated in FIG. 1, the gas supply apparatus according toEmbodiment 1 includes: a mounting table 19 (mounting portion) formounting a wafer 25 which is a substrate to be processed; and a gasejector 1 which is provided above the mounting table and supplies gasfrom a low-vacuum processing chamber 18 (processing chamber) having anopening on a bottom surface to the wafer 25 below.

The gas ejector 1 has, as main components, a primary accommodatingchamber 11, a gas supply port 12, a first-stage restricting cylinder 13(first restricting cylinder), a second-stage restricting cylinder 14(second restricting cylinder), and the low-vacuum processing chamber 18(processing chamber).

A nozzle portion 10 is formed of a configuration including a group ofthe restricting cylinders 13 and 14. That is, the nozzle portion 10 isprovided between the primary accommodating chamber 11 and the low-vacuumprocessing chamber 18.

The opening of the first-stage restricting cylinder 13 constituting thenozzle portion 10 has a circular cross-sectional shape with a diameterr1 (first diameter) on XY plane (in plan view). The first-stagerestricting cylinder 13 supplies a source gas G1 in the primaryaccommodating chamber 11 downward (in a −Z direction). The diameter r1is set such that pressure difference between the primary accommodatingchamber 11 and the low-vacuum processing chamber 18 is greater than orequal to a predetermined pressure ratio.

The second-stage restricting cylinder 14 is continuously formed with thefirst-stage restricting cylinder 13 along a Z direction. The opening ofthe bottom surface of the second-stage restricting cylinder 14 has acircular cross-sectional shape with a diameter r2 (second diameter) onXY plane (in plan view). The second-stage restricting cylinder 14supplies the source gas G1 supplied from the first-stage restrictingcylinder 13 to the low-vacuum processing chamber 18 below. The diameterr2 is set so as to satisfy “r2>r1”.

For example, the diameter r1 of the first-stage restricting cylinder 13is 1.35 mm in diameter, the depth (formation length extending in the Zdirection) of the first-stage restricting cylinder 13 is 1 mm, thediameter r2 of the second-stage restricting cylinder 14 is 8 mm indiameter, and the depth (formation length extending in the Z direction)of the second-stage restricting cylinder 14 is 4 mm. For example,nitrogen gas is supplied as the source gas G1 at a flow rate of 4 slm(standard liter per minute). Therefore, the source gas G1 that haspassed through the first-stage restricting cylinder 13 becomes anultra-high-speed gas and is supplied into the low-vacuum processingchamber via the second-stage restricting cylinder 14.

The primary accommodating chamber 11 temporarily accommodates the sourcegas G1 supplied from the gas supply port 12. The pressure in the primaryaccommodating chamber 11 is a primary pressure.

After the source gas G1 supplied from the gas supply port 12 passesthrough the primary accommodating chamber 11, a secondary pressure isdetermined by the first-stage restricting cylinder 13. The source gas G1is supplied into the low-vacuum processing chamber 18 via thesecond-stage restricting cylinder 14.

At that time, a pressure ratio PC between the primary pressure in theprimary accommodating chamber 11 and the secondary pressure in thelow-vacuum processing chamber 18 is set to greater than or equal to 30times. Then, the flow velocity of the source gas G1 that has passedthrough the first-stage restricting cylinder 13 becomes a flow velocitygreater than or equal to Mach due to the pressure ratio PC. Due to theexistence of the second-stage restricting cylinder 14, a phenomenon inwhich a Mach disk condition generated by a high-speed jet of the sourcegas G1 occurs is suppressed. Then, the source gas G1 is supplied intothe low-vacuum processing chamber 18.

For example, if the primary pressure in the primary accommodatingchamber 11 is 30 kPa and the pressure in the low-vacuum processingchamber 18 is 266 Pa, the maximum Mach number of the source gas G1 asthe ultra-high-speed gas exceeds “5” and is supplied to the wafer 25 onthe mounting table 19.

At this time, since the Mach disk condition which is likely to occur iseffectively suppressed by the existence of the second-stage restrictingcylinder 14, the gas supply apparatus can supply the gas to the wafer ata higher speed than a conventional gas supply apparatus.

That is, due to provision of the second-stage restricting cylinder 14,pressure distribution and flow-velocity distribution in the low-vacuumprocessing chamber 18 can be relaxed to avoid an occurrence of a Machdisk MD condition, and the source gas G1 is supplied into the low-vacuumprocessing chamber 18 and is supplied to the wafer 25 placed on themounting table 19 (wafer table). After the gas has been reacted, the gasis exhausted from an exhaust port 21 provided between the gas ejector 1and the mounting table 19.

(Comparison with Conventional Configuration and the Like)

FIG. 7 is an explanatory view schematically illustrating a speedcondition of a gas jet using the gas supply apparatus according toEmbodiment 1 having the nozzle portion 10.

FIG. 8 is an explanatory view schematically illustrating a pressurecondition of the gas jet using the gas supply apparatus according toEmbodiment 1 having the nozzle portion 10.

FIG. 9 is an explanatory view schematically illustrating a speedcondition of a gas jet using a conventional gas supply apparatus havinga nozzle portion configured only of a first-stage restricting cylinder13.

FIG. 10 is an explanatory view schematically illustrating a pressurecondition of the gas jet using the conventional gas supply apparatushaving the nozzle portion configured only of the first-stage restrictingcylinder 13. In FIGS. 7 to 10, the uppermost hatched portion correspondsto, for example, a formation region of an upper electrode 22 inEmbodiment 4 to be described later. In FIGS. 11 and 12, the uppermosthatched portion corresponds to the formation region of the upperelectrode 22 in Embodiment 4 to be described later.

As illustrated in FIGS. 8 and 10, the above-described pressure ratio PCof the primary pressure to the secondary pressure is set to greater thanor equal to 30 times.

As is apparent from the comparison between FIG. 7 and FIG. 9, byavoiding the phenomenon in which a Mach disk MD occurs, the gas supplyapparatus according to Embodiment 1 can supply the source gas G1 to thewafer 25 without extremely lowering the speed of the source gas G1. Incontrast, as illustrated in FIG. 9, a Mach disk MD is generated in theconventional gas supply apparatus.

FIG. 11 is an explanatory view schematically illustrating a speedcondition of a gas jet in a case where the pressure ratio PC of theprimary accommodating chamber 1 to the low-vacuum processing chamber 18is less than 30 times in the configuration according to Embodiment 1.

FIG. 12 is an explanatory view schematically illustrating a pressurecondition of the gas jet in the case where the pressure ratio PC of theprimary accommodating chamber 11 to the low-vacuum processing chamber 18is less than 30 times in the configuration in Embodiment 1. In FIGS. 11and 12, the uppermost hatched portion corresponds to the formationregion of the upper electrode 22 in Embodiment 4 to be described later.

As illustrated in FIG. 12, the above-described pressure ratio PC of theprimary pressure to the secondary pressure is set to less than 30 times.

As is apparent from the comparison between FIG. 7 and FIG. 11, in a casewhere the pressure ratio PC is greater than or equal to 30 times, speeddistribution with a higher jet velocity than that in a case where thepressure ratio PC is less than 30 times is obtained, and gas havingdirectivity can be reliably supplied to the surface of the wafer 25.

(Effects Provided by Second-Stage Restricting Cylinder 14)

FIG. 13 is an explanatory view schematically illustrating a Mach diskgeneration structure in a case of using the conventional gas supplyapparatus having the nozzle portion configured only of the first-stagerestricting cylinder 13.

In a case where when the source gas G1 which is the supply gas passesthrough the first-stage restricting cylinder 13 (orifice), the primarypressure of the primary accommodating chamber 11 is higher than thesecondary pressure of the low-vacuum processing chamber 18, that is,ejection pressure of the source gas G1 from the first-stage restrictingcylinder 13 is higher than the pressure in the low-vacuum processingchamber 18, a flow having passed through an outlet (orifice outlet) ofthe first-stage restricting cylinder 13 causes a phenomenon called ashock cell structure (shock cell), and the above shock cell structuresare periodically observed in a downstream direction. The shock cellstructure means a structure of a shock wave in which reflected shockwaves RS to be described later are repeatedly obtained at boundaryregions JB (Jet Boundary) to be described below.

Such a case where the pressure at the orifice outlet is greater than thepressure inside the low-vacuum processing chamber 18 is called underexpansion and the flow expands after passing through the orifice outlet.

In a case where the pressure at the orifice outlet is further greaterthan the pressure in the low-vacuum processing chamber 18, the gas hasnot yet fully expanded. Therefore, expansion waves EW are generated atan edge of the orifice outlet, and the gas greatly expands to theoutside. In a case where the Mach number of the gas is great, theexpansion waves EW are reflected by the boundary region JB (JetBoundary), become compression waves and return to a jet center axisside. Note that the compression wave is a wave whose pressure is higherthan a reference value. When the compression wave passes through, thepressure at the point where the compression wave passes rises. Theexpansion wave means a wave whose pressure is lower than a referencevalue. When the expansion wave passes through, the pressure at the pointwhere the expansion wave passes lowers.

As described, in a case where the pressure difference before and afterthe gas passes through the nozzle portion is great, the formedcompression waves catch up with preceding compression waves to formbarrel-shaped barrel shock waves BS (barrel shock). When the pressuredifference becomes further greater, the barrel shock waves BS cannotnormally intersect on the center axis of the jet, and in theaxisymmetric jet, a disk-shaped normal shock wave called a Mach disk MD(Mach shock wave) is formed. The flow behind the Mach disk MD is asubsonic flow. A reflected shock wave RS (Reflection Shock) is generatedfrom an end of the barrel shock wave BS. Note that a triple point TP isa point at which the barrel shock wave BS which is a compression wave,the Mach disk MD, and the reflected shock wave RS intersect.

In contrast, as illustrated in FIG. 14, in the gas ejector 1 accordingto Embodiment 1, since the second-stage restricting cylinder 14continuously formed with the first-stage restricting cylinder 13 isprovided, expanded waves EW are reflected by a side surface of thesecond-stage restricting cylinder 14, and therefore barrel shock wavesBS can normally intersect on a center axis XC of the jet. Therefore,occurrence of a Mach disk MD can be avoided.

(Effects of the Invention and the Like)

In the gas ejector 1 of the gas supply apparatus according to Embodiment1, the first-stage restricting cylinder 13 provided in the nozzleportion 10 and having the opening with the diameter r1 can givedirectivity to the source gas G1 to be ejected to the low-vacuumprocessing chamber 18. Thus, the gas can be supplied to the wafer 25which is the substrate to be processed at an ultra-high speed exceedingMach. In this case, due to existence of the second-stage restrictingcylinder 14 provided between the first-stage restricting cylinder 13 andthe low-vacuum processing chamber 18, it is possible to effectivelysuppress an occurrence of a Mach disk MD in which the ejected source gasG1 is extremely decelerated due to impact pressure and temperaturecaused by the source gas G1 ejecting at an ultra-high speed.

As a result, the gas supply apparatus according to Embodiment 1 haseffects of being able to supply the source gas G1 suitable for formationof a film having a three-dimensional structure obtained by forming afilm on a surface of the wafer 25 with high aspect ratio. For example, areactive gas is supplied as the source gas G1 to the wafer 25.

Furthermore, the gas supply apparatus according to Embodiment 1 cansupply the source gas G1 in a high-speed state to the wafer 25 which isa substrate to be processed, by setting the pressure ratio PC of theprimary pressure in the primary accommodating chamber 11 to thesecondary pressure in the low-vacuum processing chamber 18 to greaterthan or equal to 30 times.

In addition, the gas supply apparatus according to Embodiment 1 can moreeffectively suppress a Mach disk MD, by setting the diameter r2 of thesecond-stage restricting cylinder 14 to be within 30 mm in diameter.

In addition, it is preferable to adopt a first aspect where in the gassupply port 12, the primary accommodating chamber 11, the first-stagerestricting cylinder 13, and the second-stage restricting cylinder 14constituting the gas ejector 1, a gas contact region, which is a regionto be brought into contact with the source gas G1, is formed to includequartz or an alumina material as a constituent material.

A reactive gas is generally used as the source gas G1. Therefore, in thegas ejector 1 according to Embodiment 1 adopting the first aspect, atleast the above gas contact region is formed of quartz or an aluminamaterial. Since a quartz material surface and an alumina surface arechemically stable to the above-described reactive gas, it is possible tosupply the reactive gas into the low-vacuum processing chamber 18 in astate where there is little chemical reaction between the reactive gasand the gas contact region in contact with the reactive gas.

Furthermore, it is possible to reduce generation of corrosive substancesas by-products accompanying chemical reaction with the reactive gas inthe gas ejector 1. As a result, it is possible to supply, as the sourcegas G1, a clean reactive gas into the low-vacuum processing chamber 18,the reactive gas to be supplied containing no contaminants. Therefore,there is an effect of improving film-formation quality of the filmformed on the wafer 25.

Furthermore, it is preferable to adopt a second aspect where the gasejector 1 is heated to 100° C. or higher when the source gas G1 issupplied to the wafer 25, and the heated source gas G1 is supplied tothe wafer 25. Note that a configuration such as providing a heatingprocessing mechanism such as a hot plate or the like near the gasejector 1 is considered in order to perform heating processing.

In the gas supply apparatus adopting the second aspect, the reactive gasused as the source gas G1 is subjected to heating processing andreceives thermal energy. Therefore, the gas supply apparatus adoptingthe second aspect can supply a more highly reactive gas to thelow-vacuum processing chamber 18, has an effect of forming a film on thewafer 25 at a higher speed, and has an effect of being able to perform ahigh-speed film formation process.

In addition, it is preferable to adopt a third aspect where the sourcegas G1 supplied from the gas supply port 12 is a gas containing at leastnitrogen, oxygen, fluorine, and hydrogen.

In the gas supply apparatus adopting the third aspect, the source gas G1supplied from the gas supply port 12 is a gas containing at leastnitrogen, oxygen, fluorine, and hydrogen gas. Therefore, the gas supplyapparatus adopting the third aspect can be used not only for formationof an insulating film such as a nitride film or an oxide film, but alsofor resist peeling and surface treatment of the wafer 25 with highaspect ratio using an activated gas of a fluorinated gas serving as anetching gas or a cleaning gas. Furthermore, by applying anultra-high-speed gas such as a hydrogen radical gas to the surface ofthe wafer 25, the source gas G1 usable for applications other thaninsulating film formation, an etching process, and a cleaning functioncan also be supplied. Therefore, the gas supply apparatus can be usedfor various film formation processes.

In lieu of the third aspect, a fourth aspect where the source gas G1supplied from the gas supply port 12 is a precursor gas may be adopted.

By using the precursor gas as the source gas G1 supplied from the gassupply port 12, the source gas G1 can be used as a reactive gas forsurface treatment of the wafer with high aspect ratio. In addition, theprecursor gas to be a material of a deposited metal in film formation,the precursor gas necessary for film formation on the surface of thewafer 25, can be also supplied to the surface of the wafer 25 to performfilm formation.

It is preferable to adopt as a fifth aspect a configuration in which aflow rate control unit that controls the gas flow rate of the source gasG1 supplied from the gas supply port 12 is provided such that thepressure is set to a pressure lower than or equal to the atmosphericpressure (1013.25 hPa) in the low-vacuum processing chamber 18 andhigher than or equal to 10 kPa. Note that for example, a configurationin which a gas flow rate control device (mass flow controller; MFC) isprovided in a supply path between a supply unit of the source gas G1 andthe gas supply port 12 of the source gas G1, and the gas flow ratecontrol device is controlled is considered as the flow rate controlunit.

The gas supply apparatus adopting the fifth aspect can improve stabilityof the flow velocity of the ultra-high-speed gas in the source gas G1ejected from the nozzle portion 10 of the gas ejector 1 into thelow-vacuum processing chamber 18, and can exhibit the effect ofimproving film forming quality, such as uniformization of the thicknessor the like of the film formed on the surface of the wafer 25.

Embodiment 2

FIG. 2 is an explanatory view illustrating a configuration of a gassupply apparatus according to Embodiment 2 of the present invention. InFIG. 2, an XYZ orthogonal coordinate system is illustrated.

As illustrated in FIG. 2, the gas supply apparatus according toEmbodiment 2 includes: a mounting table 19 (mounting portion) formounting a wafer 25 which is a substrate to be processed; and a gasejector 2 which is provided above the mounting table 19 and supplies gasfrom a low-vacuum processing chamber 18 having an opening to the wafer25.

The gas ejector 2 includes a primary accommodating chamber 11, a gassupply port 12, a first-stage restricting cylinder 13 (first restrictingcylinder), a second-stage restricting cylinder 14 (second restrictingcylinder), a third-stage restricting cylinder 15 (third restrictingcylinder), and the low-vacuum processing chamber 18 as main components.

A nozzle portion 20 is formed of a configuration including a group ofthe restricting cylinders 13 to 15. That is, the nozzle portion 20 isprovided between the primary accommodating chamber 11 and the low-vacuumprocessing chamber 18.

Similarly to Embodiment 1, the opening of the first-stage restrictingcylinder 13 constituting the nozzle portion 20 has a circularcross-sectional shape with a diameter r1 in plan view, and supplies asource gas G1 in the primary accommodating chamber 11 downward.

The second-stage restricting cylinder 14 is continuously formed with thefirst-stage restricting cylinder 13 along a Z direction. Similarly toEmbodiment 1, the opening of the bottom surface of the second-stagerestricting cylinder 14 has a circular cross-sectional shape with adiameter r2 in plan view, and supplies the source gas G1 supplied fromthe first-stage restricting cylinder 13 downward.

The third-stage restricting cylinder 15 is continuously formed with thesecond-stage restricting cylinder 14 along the Z direction. The openingof the bottom surface of the third-stage restricting cylinder 15 has acircular cross-sectional shape with a diameter r3 (third diameter) on XYplane (in plan view). The third-stage restricting cylinder 15 suppliesthe source gas G1 supplied from the second-stage restricting cylinder 14to the low-vacuum processing chamber 18 below. The diameter r3 is set soas to satisfy “r3>r2”.

For example, in a case where the diameter r1 of the first-stagerestricting cylinder 13 is 1.35 mm in diameter, the depth of thefirst-stage restricting cylinder 13 is 1 mm, the diameter r2 of thesecond-stage restricting cylinder 14 is 8 mm and the depth of thesecond-stage restricting cylinder 14 is 4 mm, the diameter r3 of thethird-stage restricting cylinder 15 is set to 20 mm in diameter, thedepth (formation length extending in the Z direction) of the third-stagerestricting cylinder 15 is set to 46 mm, and a nitrogen gas, forexample, is supplied at a flow rate of 4 slm. Then, the source gas G1passed through the first-stage restricting cylinder 13 becomes anultra-high-speed gas and is supplied into the low-vacuum processingchamber 18 via the second-stage restricting cylinder 14 and thethird-stage restricting cylinder 15.

Note that since the other configurations of the gas ejector 2 areidentical to those of the gas ejector 1 according to Embodiment 1,identical reference signs are appropriately given, and the descriptionthereof will be omitted.

In the gas ejector 1 of the gas supply apparatus according to Embodiment2, the nozzle portion 20 is configured of the first-stage restrictingcylinder 13, the second-stage restricting cylinder 14, and thethird-stage restricting cylinder 15 having the openings with thediameter r1, the diameter r2, and the diameter r3, respectively.Therefore, it is possible to give directivity to the source gas G1ejected into the low-vacuum processing chamber 18. In this case,similarly to Embodiment 1, existence of the second-stage restrictingcylinder 14 can effectively suppress a Mach disk MD phenomenon.

In addition, the gas supply apparatus according to the Embodiment 2 haseffects similar to those of the gas supply apparatus according toEmbodiment 1, and also has the effects in the case of adopting the firstto fifth aspects.

Furthermore, the gas ejector 2 according to Embodiment 2 furtherincludes the third-stage restricting cylinder 15 as the nozzle portion20, and the diameter r3 of the third-stage restricting cylinder 15 isset to be longer than the diameter r2 of the second-stage restrictingcylinder 14. Therefore, it is possible to supply the source gas G1 tothe wafer 25 in a state where the occurrence of Mach disk MD caused bythe high-speed jet generated at the pressure ratio PC is suppressed morethan in the case of Embodiment 1.

Embodiment 3

FIG. 3 is an explanatory view illustrating a configuration of a gassupply apparatus according to Embodiment 3 of the present invention. InFIG. 3, an XYZ orthogonal coordinate system is illustrated.

As illustrated in FIG. 3, the gas supply apparatus according toEmbodiment 3 includes: a mounting table 19 (mounting portion) formounting a wafer 25 which is a substrate to be processed; and a gasejector 3 which is provided above the mounting table and supplies gasfrom a low-vacuum processing chamber 18 having an opening to the wafer25.

The gas ejector 3 includes a primary accommodating chamber 11, a gassupply port 12, a first-stage restricting cylinder 13 (first restrictingcylinder), a hemispherical restricting cylinder 17 (second restrictingcylinder), and the low-vacuum processing chamber 18 as main components.

A nozzle portion 30 is formed of a configuration including a group ofthe two restricting cylinders 13 and 17. That is, the nozzle portion 30is provided between the primary accommodating chamber 11 and thelow-vacuum processing chamber 18.

Similarly to Embodiment 1, the opening of the first-stage restrictingcylinder 13 (first restricting cylinder) constituting the nozzle portion30 has a circular cross-sectional shape with a diameter r1, and suppliesa source gas G1 in the primary accommodating chamber 11 downward.

The hemispherical restricting cylinder 17 is continuously formed withthe first-stage restricting cylinder 13 along a Z direction. The openingof the bottom surface of the hemispherical restricting cylinder 17 has acircular cross-sectional shape with a diameter r2 b (second diameter) onXY plane. The hemispherical restricting cylinder 17 supplies the sourcegas G1 supplied from the first-stage restricting cylinder 13 to thelow-vacuum processing chamber 18 below. The diameter r2 b of the bottomsurface is set so as to satisfy “r2 b>r1”.

Since the hemispherical restricting cylinder 17 is formed in ahemispherical shape having an opening at the top, the diameter r2 of theopening is set so as to increase as it goes downward (−Z direction).That is, the diameter r2 of the opening of the hemispherical restrictingcylinder 17 in plan view is set to become longer as it goes downwardfrom a diameter r2 t (=diameter r1) of the top to a diameter r2 b of thebottom surface.

Note that since the other configurations of the gas ejector 3 areidentical to those of the gas ejector 1 according to Embodiment 1,identical reference signs are appropriately given, and the descriptionthereof will be omitted.

In the gas ejector 1 of the gas supply apparatus according to Embodiment3, the nozzle portion 30 is configured of the first-stage restrictingcylinder 13 and the hemispherical restricting cylinder 17 having theopenings with the diameter r1 and the diameters r2 (r2 t to r2 b),respectively. Therefore, it is possible to give directivity to thesource gas G1 ejected into the low-vacuum processing chamber 18. In thiscase, similarly to Embodiment 1, existence of the hemisphericalrestricting cylinder 17 has the effect of suppressing a Mach disk MDphenomenon.

In addition, the gas supply apparatus according to the Embodiment 3 haseffects similar to those of the gas supply apparatus according toEmbodiment 1, and also has the effects in the case of adopting the firstto fifth aspects.

Furthermore, the hemispherical restricting cylinder 17 (secondrestricting cylinder) in the gas ejector 3 according to Embodiment 3 isformed into a hemispherical shape such that the diameter r2 of theopening becomes longer as it approaches the low-vacuum processingchamber 18 (in the −Z direction). Therefore, it is possible to supplythe source gas G1 to the wafer 25 in a state where the occurrence ofMach disk MD caused by the high-speed jet generated at the pressureratio PC is suppressed more than in the case of Embodiment 1.

Note that in the above-described configuration of Embodiment 3, as amodification, a third-stage restricting cylinder may be further providedunder the hemispherical restricting cylinder 17, similarly to thethird-stage restricting cylinder 15 according to Embodiment 2. As theshape of the third-stage restricting cylinder according to Embodiment 3,a columnar shape having a diameter identical to the diameter r2 b of thebottom surface of the hemispherical restricting cylinder 17 or the likeis considered.

Embodiment 4

FIGS. 4 and 5 are explanatory views illustrating a configuration of agas supply apparatus according to Embodiment 4 of the present invention.FIG. 4 is a cross-sectional view, and FIG. 5 is a perspective view. Ineach of FIGS. 4 and 5, an XYZ orthogonal coordinate system isillustrated.

As illustrated in FIGS. 4 and 5, the gas supply apparatus according toEmbodiment 4 includes a mounting table 19 (mounting portion) formounting a wafer 25 which is a substrate to be processed; and a gasejector 4 which is provided above the mounting table 19 and supplies gasfrom a low-vacuum processing chamber 18 having an opening to the wafer25.

The gas ejector 4 has a primary accommodating chamber 11, a gas supplyport 12, a first-stage restricting cylinder 13X (first restrictingcylinder), a second-stage restricting cylinder 14X (second restrictingcylinder), an upper electrode 22, a lower electrode 24, and thelow-vacuum processing chamber 18 as main components.

A nozzle portion 40 is formed of a configuration including a group ofthe two restricting cylinders 13X and 14X, and the lower electrode 24.That is, the nozzle portion 40 is provided between the primaryaccommodating chamber 11 and the low-vacuum processing chamber 18.

The upper electrode 22 and the lower electrode 24 each having adielectric such as alumina on surfaces facing each other are circular onXY plane (in plan view) and are provided so as to face each other. Notethat a configuration may be possible in which a dielectric is providedonly on one of the surfaces of the upper electrode 22 and the lowerelectrode 24, the surfaces facing each other.

That is, the gas ejector 4 has the upper electrode 22 and the lowerelectrode 24 (first and second electrodes) provided so as to face eachother. A discharge space is formed between the upper electrode 22 andthe lower electrode 24. At least one of the upper electrode 22 and thelower electrode 24 has a dielectric on the surface forming the dischargespace.

Specifically, the upper electrode 22 is disposed near the bottom surfacein the primary accommodating chamber 11. In contrast, the lowerelectrode 24 is arranged under the bottom surface of the primaryaccommodating chamber 11 i so as to form part of the bottom surface ofthe primary accommodating chamber 1. A through hole provided at thecenter of the lower electrode 24 serves as the first-stage restrictingcylinder 13X.

Similarly to the first-stage restricting cylinder 13 according toEmbodiment 1, the opening of the first-stage restricting cylinder 13X(first restricting cylinder) constituting the nozzle portion 40 has acircular cross-sectional shape with a diameter r1 (first diameter) on XYplane (in plan view), and supplies a source gas G1 in the primaryaccommodating chamber 11 downward.

The second-stage restricting cylinder 14X is continuously formed justunder the lower electrode 24 including the first-stage restrictingcylinder 13X along a Z direction. Similarly to the second-stagerestricting cylinder 14 according to Embodiment 1, the opening of thesecond-stage restricting cylinder 14X has a circular cross-sectionalshape with a diameter r2 (second diameter) on XY plane (in plan view),and supplies the source gas G1 supplied from the first-stage restrictingcylinder 13 to the low-vacuum processing chamber 18 below. The diameterr2 is set so as to satisfy “r2>r1”.

As described above, the gas ejector 4 according to Embodiment 4 has agas ionization unit inside. The gas ionization unit ionizes the sourcegas G1 to obtain an ionized or radicalized gas in the discharge spacebetween the upper electrode 22 and the lower electrode 24 facing eachother with the dielectric interposed therebetween.

The gas ionization unit has a discharge space between the upperelectrode 22 and the lower electrode 24 facing each other with thedielectric interposed therebetween. The gas ionization unit can apply analternating voltage between the upper electrode 22 and the lowerelectrode 24, generate dielectric-barrier discharge in the dischargespace, and supply an ionized gas or a radicalized gas obtained byionizing or radicalizing the source gas G1 into the low-vacuumprocessing chamber 18 via the second-stage restricting cylinder 14X.

As described above, the gas ejector 4 according to Embodiment 4 ischaracterized by including the gas ionization unit which is providednear a boundary region between the primary accommodating chamber 11 andthe nozzle portion 40, and produces an ionized gas or a radicalized gaswhich is an ionized or radicalized source gas obtained by ionizing thesource gas G1 supplied from the gas supply port 12.

Note that since the other configurations of the gas ejector 4 areidentical to those of the gas ejector 1 according to Embodiment 1,identical reference signs are appropriately given, and the descriptionthereof will be omitted.

In the gas ejector 1 of the gas supply apparatus according to Embodiment4, the nozzle portion 40 is configured of the first-stage restrictingcylinder 13X and the second-stage restricting cylinder 14X having theopenings with the diameter r1 and the diameter r2, respectively.Therefore, it is possible to give directivity to the source gas G1ejected into the low-vacuum processing chamber 18. In this case,similarly to Embodiment 1, existence of the second-stage restrictingcylinder 14X has the effect of capable of suppressing a Mach disk MDphenomenon.

In addition, the gas supply apparatus according to the Embodiment 4 haseffects similar to those of the gas supply apparatus according toEmbodiment 1, and also has the effects in the case of adopting the firstto fifth aspects. In this case, as heating processing according to thesecond aspect of Embodiment 4, a discharge process between the upperelectrode 22 and the lower electrode 24 can be utilized.

Furthermore, the gas ejector 4 according to Embodiment 4 can cause theabove gas ionization unit to perform gas discharge in the gas ejector 4,and can directly apply an ionized gas or a radicalized gas which is adirectional ultra-high-speed jet gas to the surface of the wafer 25 fromthe low-vacuum processing chamber 18. Therefore, as compared with theplasma CVD/ALD apparatus which is a conventional film forming apparatus,the gas ejector 4 according to Embodiment 4 can apply an activatedionized gas or an activated radicalized gas having higher density and ahigher electric field to the surface of the wafer 25, and realize ahigher-quality film formation process. The gas ejector 4 has effects ofeasily forming a film on the wafer 25 with high aspect ratio and a filmhaving a three-dimensional structure.

Furthermore, in the gas ejector 4 according to Embodiment 4, the abovegas ionization unit has the discharge space between the upper electrode22 and the lower electrode 24 facing each other with the dielectricinterposed therebetween. An alternating voltage is applied between theupper electrode 22 and the lower electrode 24, dielectric-barrierdischarge is generated in the discharge space, and an ionized gas or aradicalized gas obtained by ionizing or radicalizing the source gas G1can be supplied. At this time, considering that the ionized gas and theradical gas have very short lifetimes, in order to apply the generatedionized gas or radicalized gas to the surface of the substrate to beprocessed in a short time, a dielectric-barrier discharge mechanism (theupper electrode 22 and the lower electrode 24) is provided in the gasejector 4. Therefore, it is possible to achieve an effect of enabling ahigh-quality film formation process by using the supplied ionized gas orradicalized gas.

Specifically, the first-stage restricting cylinder 13X is configured asthe through hole formed in the lower electrode 24 (second electrode),and the discharge gas is ejected into the low-vacuum processing chamber18. Therefore, it is possible to apply the ionized gas or theradicalized gas generated by the dielectric-barrier discharge to thesurface of the wafer 25 in an extremely short time of a millisecond orless. Therefore, the gas supply apparatus according to Embodied form 4can apply even the ionized gas or the radicalized gas which is generatedby the discharge and has a very short lifetime, to the surface of thewafer 25 while suppressing attenuation to the minimum. Therefore, thegas supply apparatus has effects of enabling film formation at a lowtemperature and increasing film formation speed.

The above-described Embodiment 4 describes a case where the shape ofeach of the upper electrode 22 and the lower electrode 24 in plan viewis circular; however, it is a matter of course that the shape is notlimited to this shape.

Embodiment 5

FIG. 6 is an explanatory view illustrating a configuration of a gassupply apparatus according to Embodiment 5 of the present invention. InFIG. 6, an XYZ orthogonal coordinate system is illustrated.

As illustrated in FIG. 6, the gas supply apparatus according toEmbodiment 5 includes: a mounting table 19 (mounting portion) formounting a wafer 25 which is a substrate to be processed; and a gasejector 100 which is provided above the mounting table 19 and suppliesgas from a low-vacuum processing chamber 180 having an opening to thewafer 25.

The gas ejector 100 includes a primary accommodating chamber 110, a gassupply port 12, first-stage restricting cylinders 13 a to 13 d (aplurality of first restricting cylinders), second-stage restrictingcylinders 14 a to 14 d (a plurality of second restricting cylinders),and the low-vacuum processing chamber 180 as main components.

Nozzle portions 10 a to 10 d are formed of configurations including thefirst-stage restricting cylinders 13 a to 13 d and the second-stagerestricting cylinders 14 a to 14 d, respectively. That is, the nozzleportions 10 a to 10 d are provided between the primary accommodatingchamber 110 and the low-vacuum processing chamber 180. The nozzleportion 10 a is configured of the first-stage restricting cylinder 13 aand the second-stage restricting cylinder 14 a. The nozzle portion 10 bis configured of the first-stage restricting cylinder 13 b and thesecond-stage restricting cylinder 14 b. The nozzle portion 10 c isconfigured of the first-stage restricting cylinder 13 c and thesecond-stage restricting cylinder 14 c. The nozzle portion 10 d isconfigured of the first-stage restricting cylinder 13 d and thesecond-stage restricting cylinder 14 d.

Similarly to the first-stage restricting cylinder 13 according toEmbodiment 1, the opening of each of the first-stage restrictingcylinders 13 a to 13 d (plurality of first restricting cylinders) has acircular cross-sectional shape with a diameter r1 in plan view, andsupplies a source gas G1 in the primary accommodating chamber 110downward.

The second-stage restricting cylinders 14 a to 14 d (second restrictingcylinders) are continuously formed with the first-stage restrictingcylinders 13 a to 13 d along a Z direction, respectively. Similarly tothe second-stage restricting cylinder 14 according to Embodiment 1, theopening of each of the second-stage restricting cylinders 14 a to 144has a circular cross-sectional shape with a diameter r2 in plan view.The second-stage restricting cylinders 14 a to 14 d supply downward thesource gas G1 supplied from the first-stage restricting cylinder 13 a to13 d, respectively. After the gas has been reacted, the gas is exhaustedfrom an exhaust port 210 provided between the gas ejector 100 and themounting table 19.

Note that since the other configurations of the gas ejector 100 aresimilar to those of the gas ejector 1 according to Embodiment 1,identical reference signs are appropriately given, and the descriptionthereof will be omitted.

In the gas ejector 1 of the gas supply apparatus according to Embodiment5, the nozzle portions 10 a to 10 d (the plurality of nozzle portions)are configured of the first-stage restricting cylinders 13 a to 13 d andthe second-stage restricting cylinders 14 a to 14 d having the diameterr1 and the diameter r2, respectively. Therefore, it is possible to givedirectivity to the source gas G1 ejected into the low-vacuum processingchamber 180. In this case, similarly to Embodiment 1, existence of thesecond-stage restricting cylinders 14 a to 14 d provides an effect ofeffectively suppressing a Mach disk MD phenomenon.

In addition, the gas supply apparatus according to the Embodiment 5 haseffects similar to those of the gas supply apparatus according toEmbodiment 1, and also has the effects in the case of adopting the firstto fifth aspects.

Furthermore, the gas ejector 100 according to Embodiment 5 can uniformlyapply high-speed gas having directivity from the nozzle portions 10 a to10 d (the plurality of nozzle portions) to the entire surface of thewafer 25, and can perform a high-quality and uniform film formationprocess in a relatively short time even upon film formation on the wafer25 with high aspect ratio and upon three-dimensional film formation onthe surface of the wafer 25 having a three-dimensional structure.

In addition, a sixth aspect may be adopted in which when the diametersr1 of the first-stage restricting cylinders 13 a to 13 d are set todiameters r1 a to r1 d, the diameters r1 a to r1 d are set to differentvalues. That is, the sixth aspect may be adopted in which the diametersr1 of the nozzle portions 10 a to 10 d differ from one another.

In the gas supply apparatus according to Embodiment 5 adopting the sixthaspect, flow rates and speeds of gas ejected from the nozzle portions 10a to 10 d are controlled such that the flow rates and the speeds differfrom one another. Therefore, for example, if the gas amounts of thesource gas G1 containing an ionized gas, a radicalized gas, or the likeejected from the nozzle portions 10 a to 10 d are independentlycontrolled correspondingly to the locations on the surface of the wafer25 where the gas hits, an effect is provided that leads to animprovement in film formation quality such as uniform film formation onthe entire surface of the wafer 25.

In addition, a seventh aspect may be adopted in which the structure ofeach of the nozzle portions 10 a to 10 d is similar to that of thenozzle portion 40 according to Embodiment 4, and a plurality of gasionization units provided correspondingly to the nozzle portions 10 a to10 d can be controlled independently.

The plurality of gas ionization units provided correspondingly to thenozzle portions 10 a to 10 d (the plurality of nozzle portions) can becontrolled independently. Therefore, by controlling the plurality ofejected gas amounts of the ionized gas or the radicalized gas anddischarge power, the gas amount of the ionized gas or the radicalizedgas to be ejected and the discharge power can be controlledcorrespondingly to the location on the surface of the wafer 25 where thegas hits. As a result, the seventh aspect in the gas supply apparatusaccording to Embodiment 5 provides an effect that leads to animprovement in film formation quality such as uniform film formation onthe entire surface of the wafer 25.

Note that in Embodiment 5 described above, the structure similar to thatof the nozzle portion 10 according to Embodiment 1 is adopted as thestructure of each of the nozzle portions 10 a to 10 d. However, as thestructure of each of the nozzle portions 10 a to 10 d, a structuresimilar to that of the nozzle portion 20 according to Embodiment 2, thenozzle portion 30 according to Embodiment 3, or the nozzle portion 40according to Embodiment 4 may be adopted.

In the sixth aspect of Embodiment 5, when the diameters r1 of thefirst-stage restricting cylinders 13 a to 13 d are set to the diametersr1 a to r1 d, the diameters r1 a to r1 d are set to values differentfrom one another. Furthermore, when the diameters r2 of the second-stagerestricting cylinders 14 a to 14 d are set to diameters r2 a to r2 d,the diameters r2 a to r2 d may be set to values different from oneanother (a first modification). In addition, in the case of theconfiguration where each of the nozzle portions 10 a to 10 d accordingto Embodiment 5 further includes a third-stage restricting cylinder 15(15 a to 15 d) as in Embodiment 2, when diameters r3 of the third-stagerestricting cylinders 15 a to 15 d are set to diameters r3 a to r3 d,the diameters r3 a to r3 d may be set to values different from oneanother (a second modification).

In the gas supply apparatus according to Embodiment 5 adopting the firstand second modifications of the sixth aspect, flow rates and speeds ofgas ejected from the nozzle portions 10 a to 10 d are variablycontrolled such that the flow rates and the speeds differ from oneanother. In addition, even in a case where each of the nozzle portions10 a to 10 d has the configuration of the nozzle portion 30 according toEmbodiment 3 or the configuration of the nozzle portion 40 according toEmbodiment 4, the above-described first or second modification may beadopted and the diameters r2 (including the diameters of the third-stagerestricting cylinders according to the modification) of thehemispherical restricting cylinders 17, the diameters r2 of thesecond-stage restricting cylinders 14X, or the like may be set todifferent values among the nozzle portions 10 a to 10 d.

<Others>

In the above-described embodiments, the maximal number of stages ofrestricting cylinders is three (Embodiment 2). However, a configurationof providing four or more stages of restricting cylinders is naturallyconsidered, such as providing a fourth-stage restricting cylinder belowthe third-stage restricting cylinder 15 according to Embodiment 2.

While the present invention has been described in detail, the foregoingdescription is in all aspects illustrative and the present invention isnot limited thereto. It is understood that innumerable modifications notillustrated can be envisaged without departing from the scope of thepresent invention.

EXPLANATION OF REFERENCE SIGNS

-   -   1 to 4, 100: gas ejector    -   11, 110: primary accommodating chamber    -   12: gas supply port    -   13, 13 a to 13 d, 13X: first-stage restricting cylinder    -   14, 14 a to 14 d, 14X: second-stage restricting cylinder    -   15: third-stage restricting cylinder    -   17: hemispherical restricting cylinder    -   18, 180: low-vacuum processing chamber    -   19: mounting table    -   22: upper electrode    -   24: lower electrode    -   25: wafer

1: A gas supply apparatus comprising: a mounting portion for mounting asubstrate to be processed; and a gas ejector which is provided abovesaid mounting portion and supplies gas from a processing chamber havingan opening on a bottom surface to said substrate to be processed,wherein said gas ejector includes: a primary accommodating chamber whichtemporarily accommodates gas supplied from a gas supply port; saidprocessing chamber; and a nozzle portion which is provided between saidprimary accommodating chamber and said processing chamber, said nozzleportion has: a first restricting cylinder whose opening has a circularcross-sectional shape with a first diameter in plan view, and whichsupplies the gas in said primary accommodating chamber downward; and asecond restricting cylinder whose opening has a circular cross-sectionalshape with a second diameter in plan view, and which supplies the gassupplied from said first restricting cylinder to said processingchamber, said first diameter is set such that pressure differencebetween said primary accommodating chamber and said processing chamberis not less than a predetermined pressure ratio, and said seconddiameter is set to be longer than said first diameter. 2: The gas supplyapparatus according to claim 1, wherein said predetermined pressureratio is 30 times, said first diameter of said first restrictingcylinder is set to be not greater than 2 mm in diameter and a formationlength of said first restricting cylinder is set to be not greater than2 mm, and pressure difference between pressure in said primaryaccommodating chamber and pressure in said processing chamber is set tobe not less than 30 times. 3: The gas supply apparatus according toclaim 1, wherein said second diameter of said second restrictingcylinder is set within 30 mm in diameter. 4: The gas supply apparatusaccording claim 1, wherein said nozzle portion further includes a thirdrestricting cylinder whose opening has a circular cross-sectional shapewith a third diameter in plan view, and which supplies the gas suppliedfrom said second restricting cylinder to said processing chamber, andsaid third diameter is longer than said second diameter. 5: The gassupply apparatus according to claim 1, wherein said second restrictingcylinder in said nozzle portion is formed into a hemispherical shapesuch that said second diameter becomes longer as said second restrictingcylinder approaches said processing chamber. 6: The gas supply apparatusaccording to claim 1, wherein a gas contact region which is a region tobe brought into contact with gas in said gas ejector is formed toinclude one of quartz and an alumina material as a constituent material.7: The gas supply apparatus according to claim 1, wherein said gasejector is heated to not lower than 100° C. so as to supply heated gasto said substrate to be processed. 8: The gas supply apparatus accordingto claim 1, wherein the gas supplied from said gas supply port is gascontaining at least nitrogen, oxygen, fluorine, and hydrogen. 9: The gassupply apparatus according to claim 1, wherein the gas supplied fromsaid gas supply port is a precursor gas. 10: The gas supply apparatusaccording to claim 1, wherein a gas flow rate of the gas supplied fromsaid gas supply port is controlled such that pressure in said primaryaccommodating chamber is set to be not higher than atmospheric pressureand not lower than 10 kPa. 11: The gas supply apparatus according toclaim 1, wherein said nozzle portion includes a plurality of nozzleportions. 12: The gas supply apparatus according to claim 11, whereinsaid first diameters of said first restricting cylinders in saidplurality of nozzle portions are set to different values. 13: The gassupply apparatus according to claim 1, further comprising: a gasionization unit which is provided near a boundary region between saidprimary accommodating chamber and said nozzle portion, and produces oneof an ionized gas and a radicalized gas by ionizing the gas suppliedfrom said gas supply port. 14: The gas supply apparatus according toclaim 13, wherein said gas ionization unit has a first electrode and asecond electrode provided so as to face each other and has a dischargespace between said first electrode and said second electrode, and atleast one of said first electrode and said second electrode has adielectric on a surface forming said discharge space, said firstrestricting cylinder is formed of a through hole formed in said secondelectrode, and one of said ionized gas and said radicalized gas issupplied to said processing chamber, the one of said ionized gas andsaid radicalized gas being obtained by applying an alternating voltagebetween said first electrode and said second electrode, and generatingdielectric-barrier discharge in said discharge space. 15: The gas supplyapparatus according to claim 13, wherein said nozzle portion includes aplurality of nozzle portions, and said gas ionization unit includes aplurality of gas ionization units provided correspondingly to saidplurality of nozzle portions, and said plurality of gas ionization unitsare independently controllable.